INT 2F - DR-DOS 6.0 TaskMAX - GET/SET TEXT PASTE LEAD-IN
        AX = 270Eh
        CX = length of string (max 15 keystrokes, 0000h to get current string)
        DS:SI -> pasting lead-in string (character/scan-code pairs)
Return: ES:DI -> current lead-in string
Note:   the specified sequence of keystrokes is sent to the application before
          every line of a text-mode spreadsheet paste
SeeAlso: AX=2710h,AX=2713h